90+ Data Analyst Intern Interview Questions and Answers

Pick a fruit from the jar labeled Apples and Oranges, then pick a fruit from the jar labeled Oranges (since it can't be Oranges), and finally pick a fruit from the jar labeled Apples (since it can't be Apples).

• Pick a fruit from the jar labeled Apples and Oranges

• Since the jar labeled Oranges can't be Oranges, it must be Apples and Oranges

• The remaining jar must be Apples

Data is information collected and stored for analysis and decision-making purposes in an organization.

• Data is raw facts and figures that need to be processed to provide meaningful information.

• It is crucial for organizations to make informed decisions, identify trends, and improve performance.

• Examples of data in an organization include sales figures, customer demographics, and website traffic.

• Data can be structured (in databases) or unstructured (like text documents or social ...read more

Python code to check if a sentence is palindrome or not

• Remove all spaces and convert to lowercase

• Reverse the string and compare with original

• If both are same, then it is a palindrome

RDBMS is a relational database management system. Objects in a database include tables, views, indexes, functions, stored procedures, constraints, and foreign keys. OLAP is for data analysis while OLTP is for transaction processing.

• RDBMS stands for Relational Database Management System

• Objects in a database include tables, views, indexes, functions, stored procedures, constraints, and foreign keys

• OLAP (Online Analytical Processing) is used for data analysis and reporting

• OLTP (...read more

Separate lines in standard output in C++ are used to display different pieces of information on separate lines for better readability.

• Separate lines are used to display different outputs or messages in a clear and organized manner.

• They are commonly used with the 'endl' or ' ' characters to move to the next line.

• For example, cout << 'Hello' << endl; will display 'Hello' on one line and move to the next line for the next output.

Hash map is a data structure that stores key-value pairs and allows fast retrieval of values based on keys.

• Hash map uses hashing to store and retrieve values based on keys

• It allows null values and null keys

• It is not synchronized and not thread-safe

• Example: HashMap map = new HashMap<>();

• map.put("apple", 1); int value = map.get("apple");

List of SQL languages and their brief explanation

• SQL (Structured Query Language) is a standard language for managing relational databases

• T-SQL (Transact-SQL) is a proprietary extension of SQL used by Microsoft SQL Server

• PL/SQL (Procedural Language/Structured Query Language) is Oracle Corporation's proprietary extension of SQL

• MySQL is an open-source relational database management system that uses SQL

• PostgreSQL is an open-source object-relational database management system that...read more

Super key is a set of attributes that uniquely identifies a record, while foreign key is a reference to a primary key in another table.

• Super key is a combination of one or more attributes that uniquely identifies a record in a table.

• Foreign key is a field in a table that refers to the primary key of another table.

• Super key can have additional attributes that are not necessary for uniqueness.

• Foreign key establishes a relationship between two tables.

• Example: In a database of st...read more

4-stroke engines have 4 strokes per cycle, while 2-stroke engines have 2 strokes per cycle.

• 4-stroke engines are more fuel-efficient and produce less pollution than 2-stroke engines.

• 2-stroke engines are simpler and lighter than 4-stroke engines.

• 4-stroke engines have separate intake, compression, power, and exhaust strokes, while 2-stroke engines combine intake and compression, and power and exhaust strokes.

• Examples of 4-stroke engines include those found in cars, while example...read more

A double linked list is a data structure where each node contains a reference to the previous and next node.

• In a linked list, each node contains a reference to the next node only, while in a double linked list, each node contains references to both the previous and next nodes.

• Double linked lists allow for traversal in both directions, making operations like deletion and insertion easier compared to single linked lists.

• Example: In a double linked list, a node might have pointe...read more

Outliers in a boxplot are defined as data points that fall below Q1 - 1.5*IQR or above Q3 + 1.5*IQR.

• Calculate the interquartile range (IQR) by subtracting Q1 from Q3.

• Identify the lower bound as Q1 - 1.5*IQR and the upper bound as Q3 + 1.5*IQR.

• Any data points below the lower bound or above the upper bound are considered outliers.

• For example, if Q1 = 10, Q3 = 20, and IQR = 5, then the lower bound = 10 - 1.5*5 = 2.5 and the upper bound = 20 + 1.5*5 = 27.5.

Power BI is a business analytics tool used to visualize and analyze data. Power Query is a data transformation and shaping tool in Power BI.

• Power BI is a powerful business intelligence tool developed by Microsoft.

• It allows users to connect to various data sources, transform and clean the data, and create interactive visualizations and reports.

• Power BI enables data analysts to gain insights and make data-driven decisions.

• Power Query is a data transformation and shaping tool wi...read more

Memory management and hash map are important concepts in Java programming.

• Memory management is the process of allocating and deallocating memory in a program.

• Java uses automatic memory management through garbage collection.

• Hash map is a data structure that stores key-value pairs and uses hashing to retrieve values efficiently.

• Java's HashMap class implements the Map interface and provides constant-time performance for basic operations.

• It is important to properly manage memory ...read more

Creating a data frame in Python and performing statistical analysis on it.

• Import pandas library to create a data frame

• Use numpy library to generate random data for the data frame

• Perform statistical analysis using pandas functions like mean, median, and standard deviation

SQL joins are used to combine rows from two or more tables based on a related column between them. Window functions perform calculations across a set of table rows that are related to the current row.

• SQL joins are used to retrieve data from multiple tables based on a related column between them (e.g. INNER JOIN, LEFT JOIN, RIGHT JOIN, FULL JOIN).

• Window functions are used to perform calculations on a set of rows related to the current row (e.g. ROW_NUMBER(), RANK(), LAG(), LEA...read more

The dataset consists of customer purchase history and demographic information. Difficulties faced include data cleaning and missing values.

• Dataset includes customer ID, purchase amount, purchase date, age, gender, and location.

• Difficulties faced include handling missing values in the age and location columns.

• Data cleaning involved removing duplicates and outliers to ensure accurate analysis.

• Normalization and standardization of data for model preparation.

Use SQL query with WHERE clause to pull data from a table based on a time interval.

• Use SQL query with SELECT statement to specify the columns you want to retrieve.

• Add a WHERE clause with the condition for the time interval, using appropriate date/time functions.

• Example: SELECT * FROM table_name WHERE timestamp_column BETWEEN 'start_time' AND 'end_time';

To maximize sales on a state level, focus on market research, targeted marketing strategies, strong customer service, and strategic partnerships.

• Conduct market research to understand the local consumer behavior and preferences

• Implement targeted marketing strategies based on the research findings

• Provide excellent customer service to build loyalty and attract repeat business

• Form strategic partnerships with local businesses or organizations to expand reach and customer base

Approximately 500 paper cups may be used in a day in an average office.

• Consider the number of employees in the office

• Think about the average number of hot beverage drinkers

• Factor in the number of meetings and events held in the office

• Take into account the availability of reusable cups

• Estimate based on personal experience or observation

Primary key uniquely identifies a record while candidate key can also uniquely identify a record but may not be chosen as primary key.

• Primary key is a column or set of columns that uniquely identifies each record in a table

• Candidate key is a column or set of columns that can also uniquely identify each record in a table

• A table can have multiple candidate keys but only one primary key

• Primary key cannot have null values while candidate key can have null values

• Example: In a tabl...read more

I have worked on projects involving customer segmentation, sales forecasting, and sentiment analysis using analytics.

• Customer segmentation: Used clustering algorithms to group customers based on their behavior and demographics.

• Sales forecasting: Utilized time series analysis to predict future sales trends and optimize inventory management.

• Sentiment analysis: Applied natural language processing techniques to analyze customer feedback and sentiment towards products or services.

The latest project consumed approximately 500 MB of data.

• The latest project consumed 500 MB of data.

• It is important to track data consumption for future optimization.

• Weaknesses can include lack of experience with certain tools or techniques.

• Weaknesses can also include difficulty in time management or communication.

Delete removes specific rows from a table, drop removes entire table structure, and truncate removes all rows from a table.

• Delete is a DML command, drop is a DDL command, and truncate is a DDL command.

• Delete can be rolled back, drop cannot be rolled back, and truncate cannot be rolled back.

• Delete triggers delete triggers, drop triggers drop triggers, and truncate does not trigger any triggers.

• Example: DELETE FROM table_name WHERE condition;

• Example: DROP TABLE table_name;

• Examp...read more

Tableau offers various types of graphs like bar charts, line charts, scatter plots, etc. for visualizing data.

• Bar charts: used to compare different categories or show trends over time

• Line charts: show trends over time or relationships between variables

• Scatter plots: show relationships between two numerical variables

• Pie charts: show parts of a whole or percentages

• Heat maps: show data density or relationships in a matrix format

List of SQL languages

• MySQL

• Oracle

• PostgreSQL

• Microsoft SQL Server

• SQLite

Exception handling in Java allows for the handling of errors and exceptions that may occur during program execution.

• Java provides try-catch blocks to handle exceptions.

• The try block contains the code that may throw an exception.

• The catch block catches and handles the thrown exception.

• Multiple catch blocks can be used to handle different types of exceptions.

• The finally block is optional and is executed regardless of whether an exception occurs or not.

• Exceptions can also be thr...read more

Company is a tech startup specializing in data analytics. Work culture is collaborative and innovative.

• Company specializes in data analytics for various industries such as e-commerce and healthcare

• Work culture is collaborative, with team members encouraged to share ideas and work together on projects

• Innovative approach to problem-solving, with emphasis on using cutting-edge technology and tools

• Regular team building activities and opportunities for professional development

Memory management in Java involves automatic garbage collection and manual memory allocation.

• Java uses automatic garbage collection to free up memory

• Developers can manually allocate memory using the 'new' keyword

• Java also has a 'finalize' method to clean up resources before garbage collection

• Memory leaks can occur if objects are not properly released

Data analysis focuses on analyzing data to extract insights, while data science involves a broader range of skills including machine learning and programming.

• Data analysis involves analyzing data to extract insights and make informed decisions.

• Data science involves a broader range of skills including machine learning, programming, and statistical modeling.

• Data analysis is more focused on descriptive and diagnostic analytics, while data science also includes predictive and pre...read more

OOPs stands for Object-Oriented Programming. It is a programming paradigm based on the concept of objects, which can contain data and code.

• OOPs is a programming paradigm that uses objects to structure code.

• It focuses on data encapsulation, inheritance, polymorphism, and abstraction.

• Examples of OOP languages include Java, C++, and Python.

Convert Json Data to Pandas Dataframe

• Use the pandas library to import the json data

• Use the pandas.DataFrame() function to convert the json data into a dataframe

• Specify the required columns in the dataframe

Logistic regression model evaluation involves assessing its performance using metrics like accuracy, precision, recall, and F1 score.

• Evaluate model performance using metrics like accuracy, precision, recall, and F1 score.

• Use confusion matrix to calculate true positives, true negatives, false positives, and false negatives.

• Calculate accuracy as (TP + TN) / (TP + TN + FP + FN).

• Calculate precision as TP / (TP + FP).

• Calculate recall as TP / (TP + FN).

• Calculate F1 score as 2 * (pr...read more

A bevel gear is a type of gear used to transmit power between shafts at an angle.

• Bevel gears have conical shapes and are used to change the direction of rotation.

• They are commonly used in automobiles, airplanes, and power plants.

• An example of a bevel gear is the ring and pinion gear in a car's differential.

• Another example is the bevel gear used in a hand drill to transmit power from the motor to the chuck.

Exceptional handling in Java is a mechanism to handle runtime errors and prevent program crashes.

• Java provides try-catch blocks to handle exceptions

• Multiple catch blocks can be used to handle different types of exceptions

• Finally block is used to execute code regardless of whether an exception is thrown or not

Oops concepts are fundamental to Java programming and include inheritance, polymorphism, encapsulation, and abstraction.

• Inheritance allows a class to inherit properties and methods from a parent class.

• Polymorphism allows objects to take on multiple forms and behave differently based on their context.

• Encapsulation hides the implementation details of a class and only exposes necessary information.

• Abstraction focuses on the essential features of an object and hides unnecessary d...read more

Use a balance scale to compare groups of balls to find the heavier one.

• Divide the 9 balls into 3 groups of 3 balls each.

• Weigh 2 of the groups against each other. If one group is heavier, move to the next step.

• If both groups weigh the same, the heavier ball is in the remaining group of 3 balls.

• Take the heavier group of 3 balls and weigh 2 of them against each other.

• If one ball is heavier, that is the answer. If they weigh the same, the remaining ball is the heavier one.

Normalization and standardization are techniques used to rescale data to have a mean of 0 and a standard deviation of 1.

• Normalization is the process of rescaling the data to have values between 0 and 1.

• Standardization is the process of rescaling the data to have a mean of 0 and a standard deviation of 1.

• Normalization is useful when the features have different ranges.

• Standardization is useful when the features have different units of measurement.

• Example: Normalization - Min-Ma...read more

To be a data analyst, one needs strong analytical skills, proficiency in data manipulation and visualization, and knowledge of statistical techniques.

• Strong analytical skills to identify trends and patterns in data

• Proficiency in data manipulation using tools like SQL, Python, or R

• Ability to visualize data and communicate insights effectively

• Knowledge of statistical techniques for data analysis

• Familiarity with data cleaning and preprocessing techniques

• Understanding of data mod...read more

I received comprehensive training in data quality analysis at AISECT.

• The training covered data cleaning techniques and tools

• I learned how to identify and resolve data quality issues

• Practical exercises helped me apply the concepts learned in real-world scenarios